Here it is in use:
I had only done preliminary testing until just now at lunch time. For my main lens, here's what I found, using 10 readings at each speed:
| Setting (sec) | Avg. Reading (micro sec) | Std. Dev. | Effective Shutter Speed (sec) |
|---|---|---|---|
| 1/50 | 19157 | 665.52 | 1/52.2 |
| 1/100 | 10427 | 129.89 | 1/95.9 |
| 1/200 | 6599 | 49.58 | 1/151.5 |
| 1/400 | 5064 | 450.35 | 1/197.5 |
So, it looks like 1/200 s is overexposing by a half stop, and 1/400 is really like 1/200. I haven't really used 1/400 much because it seemed kind of fragile (I can feel it uses a different set of springs which are obviously getting tired. The really slow speeds and bulb setting don't work at all.) The other two speeds are satisfactory.
I have been trying to think of ways I can calibrate my tester. Any ideas? I looked at the data sheet for the sensor, and the rise time and fall time are only 5 micro sec. different, which I could account for but in terms of my camera hardware it's insignificant. The film I use (Tri-X Pan) can be safely exposed +- a full stop.